Method for making articles having transparencies and the resulting articles



Aug. 12, 1941. R. L. GRAY 2,251,930

METHOD FOR MAKING ARTICLES HAVING TRANSPARENCIES INVENTOR. E 5527 Gear 0 yg W $2 A TTTTT Y.

Patented Aug. 12, 1941 METHOD FOR MAKING ARTICLES HAVING TRANSPARENCIES AND THE RESULTING ARTICLES Robert L. Gray, Brooklyn, N. Y., assignor to The Gray Envelope Manufacturing Company, Inc., Brooklyn, N. Y., a corporation of New York Application June 16, 1986, Serial No. 213,996

15 Claims.

This invention relates to methods for uniting paper and a transparency-more particularly to uniting envelope or'container stock with a transparency, such as the uniting of a window envelope patch for window envelopes and like containers, and the resulting products.

This application is a continuation in part of my application Serial No. 675,688, filed June 14, 1933 now Patent No. 2,129,686, granted September 13, 1938, which patent relates to certain improvements over my invention now Patent No. 2,072,875, granted March 9, 1937.

In my Patent 2,072,875 aforementioned, there are described, among other things, methods for securing an extremely intimate bond between the patch forming the transparency for the window envelopes and the envelope or container body which, among other things, may be extended to acquire in addition to the intimacy of bond, a condition wherein loose edges at the periphery of the cutout and/or the periphery of the patch are avoided.

In said Patent 2,072,875 I have claimed the application of an adhesive coating to the container or envelope body or the patch forming the transparency. For application of the thermoplastic adhesive on the container or envelope body, registry about the window cutout is necessary.

I have found that the labor of registry about the window cutout of the container or envelope body of the application of an adhesive film or an activator for an adhesive film may be avoided and certain additional novel advantages may be obtained by a continuous coating of a. film upon the container or envelope blank as a preliminary step, uniting therewith a transparency in the form of a patch or otherwise. Particularly where such coating includes opacifying or writing obliterating ornamentation, there is possible a high speed operation and an intimacy of union which is not attainable solely by heat and pressure described in my aforementioned patent.

Among the objects of my invention reside the provision of a process for treating the container or envelope blank more or less to continously coat the same with a film forming material or an impregnating material which is extremely compatible or has an afiinity for the thermoplastic coating of a transparency, such as the window envelope patch, so that upon pressure, with or without heat or additional solvent activation, high speed production is possible.

Other objects of my invention reside in providing a continuous coating on the envelope or container body which includes opacifying tinting material or ornamentation so that light weight stock may be employed for the container or envelope body, serving to confuse and make indiscernible any writing contained Within the envelope or container.

Other objects and advantages of my invention, in the mode of operation and the resultant product, will appear more clearly as this description proceeds and, for purposes of exemplification, I make reference to the accompanying drawing, forming a part hereof, in which- Figure l is a fragmentary plan view of paper stock showing one embodiment of my invention;

Figure 2 is a plan view of an envelope blank made therefrom;

Figure 3 is the envelope blank having adhered thereto a transparency or patch;

Figure 4 is a section taken on the line 4-4 of Figure 2;

Figure 5 is a section taken on the line 5-5 of Figure 3;

Figure 6 is a plan View of another embodiment of my invention;

Figure 7 is a section taken on the line l'! of Figure 6.

Making reference to the drawing, it is contemplated by my invention, as described in my application Serial No. 675,688, now Patent No. 2,129,686, to provide a paper stock 19, with a coating H. The coating I! is shown shaded and this is merely representative of a continuous film or paper impregnation as may be applied at any stage following immediately after the formation of the paper, and may include tinting or opacifying, pigments or a printing of an ornamenting design intended to opacify the paper so that when formed in an envelope, the contents thereof may not be discernible to one who may hold the closed envelope against a light source, or the coating or paper treatment ll may be in the form of an ornamental design or printing matter which so blends with any printing upon the contents of the envelope when filled, such as a check, so that the figures thereon may not be read through the envelope, when holding the sealed envelope against a light source.

In such paper treatment, a film forming material which is thermoplastic or organic solvent activatable or both, together with a pigment serving to opacify the envelope paper, may be employed, thereby permitting a thinner grade of paper to be employed. The constituents of the coating generally may reside in a film forming material, such as a cellulose compound, cellulose nitrate, cellulose acetate, resinous materials, a plasticizer and a dye or a pigment.

'The coating may be applied at the paper mill or applied by printing rolls, etched plates, by a brushing or spraying operation, preferably in the form of an intaglio ink. The coating may be continuous or may be intermittent by dots or spottings characteristics of half tone plates.

In the illustration given, the paper l0, coated with the coating I I as described, is illustrated in the form of a film in which the coating II is in the form of discontinuous dots, as may be obtained by an etched plate or half tone plate, leaving microscope spaces I2 therebetween, as will be more clearly apparent from an inspection of Figures 4 and 5. These views are highly magnified for purposes of illustration. The composition of the coating I l is as already stated and the binder and plasticizer therein contained are of such character as to be compatible with the transparency which may be applied in the form of a patch.

, With such a web provided, there may be cut therefrom an envelope blank I3, defined by the dotted lines shown in Figure 1, to outline the blank asmore' specifically shown in Figure 2.

Thereafter, a window opening it may be cut therefrom. This blank in the form of side flaps I5, a sealing flap I6, may have applied thereto a flap sealing gum IT, on the sealing flap I6.

The nature of the coating II, either by reason of the mode of application in the form of minute dots or by reason of the plasticizer which may be employed, is compatible with the gum I1.

- In the same manner, as part of the envelope forming procedure, the blank may have affixed to the back flap I8, applications of gum I9. This gum coating, though of the water soluble type, as in connection with the gum coating [7, is compatible with the coating II initially applied to the paper stock IIJ, either by reason of the plasticizer employed in the binder forming the ink of the coating II or by reason of the spacial pressure in applying the patch 2i] serves to weld the coatings I I Figure 5.

As already mentioned in my issued Patent 2,072,875 and my copending application now and 2! together, as shown in Patent No. 2,129,686, the patch 20 may be a glassine paper having a coating 2| of a nitrocellulose plasticized base, responsive to heat and pressure or heat, pressure and solvent, to activate the same to adhesiveness. Under such conditions, the coating II is made of a printing ink interior surface of the envelope, serving to opacify the envelope. This permits light weight paper to be employed, in addition to the conjoint function of speeding up the sealing operation of the patch to the envelope blank.

Should the coating ll be of material incompatible with water soluble gums, such as the coatings I1 and I9, necessary for forming the sealing flap or for holding down the sealing flap H5 in the final article or for uniting in position the back flap I8, the spacial relationship of the coating II, leaving uncoated portions I2, will permit the gum I! or It! to enter into the interstitial space I2, to unite with the paper I ll, which may be more compatible with water soluble gums than the coating I I.

By using half tones or etched plates, which leave a discontinuous coating when viewed under magnification, notwithstanding the application of the coating II, the paper stock so coated is compatible with water soluble gums and, therefore, does not interfere with the existing methods of applying a water soluble gum I1 and I9 to the sealing and back flaps, respectively, for completing the envelope operations.

The nature of the coating II may be adjusted with due regard to the nature of the patch 29. 'In my prior mentioned Patent No. 2,072,875 and application now Patent No. 2,129,686, I have referred to glassine paper with a plasticized nitrocellulose coating, nitrocellulose foils, cellulose acetate foils, synthetic resin foils, Cellophane foils (regenerated cellulose), plain or coated with a moistureproofing or waterproofing coating, such as nitrocellulose, a plasticizer, resin and wax.

For coated patches from the group enumerated, including those which are also described in my issued Patent No. 2,072,875 and copending application now Patent No. 2,129,686, the coating II is chosen to be compatible therewith and a nitrocellulose base coating containing a plasticizer from 5 to 15%, with or without resins, may first be applied in suitable solvents, by the methods hereinbefore described, immediately after the paper making stage in continuous rolls, from which the blank I3 may be cut or, at the time that the blank without the coating is fed into the container forming machine, such as envelope making machines and as the work progresses the coating II as substantially dried, has applied thereto the'gum coatings I! and I9, and is then fed to the patch applying contrivance where the patch 20 is pressed into position, preferably with heat. The process is so timed that the coating I I is substantially dry as it enters into the patch sealing stage, thereby permitting simultaneous folding of the envelope, to complete the envelope forming operation, by folding the side flaps I5 and the back flap I8 thereover into sealing position. Sufiicient folding of the sealing fiap I5, in a partially upstanding position, may be simultaneously accomplished, in a manner readily understood with the various envelope forming machines known and more specifically described in my hereinbefore mentioned Patent No. 2,072,875 or my application Serial No. 126,154, filed Feb. 117, I937.

V Where the patch 20 is plain Cellophane or uncoated transparencies or substantial transparenci'es, the coating II may solely serve as the in termediate thermoplastic or solvent activatable film for uniting the transparency to the body of the envelope in overlapping position, as shown in Figure 3. Preferably, however, the coating II is, under these conditions, so chosen as to have a plasticizer for the nitrocellulose, cellulose acetate or rsin binder, which is compatible with the transparency, and plasticizers such as the high boiling Cellosolves (ethylene glycol mono-n butyl ether; ethylene glycol mono-ethyl ether monoacetate), thereby providing a coating which though normally dry, as in the prior examples, is compatible with uncoated materials, such as normal Cellophane or glassine paper, or even normally dry and hardened gum coated transparencies so that the heat and pressure in uniting the patch will render the thermoplastic coating H compatible with the transparency 20.

It will be understood that each of the coatings II is preferably of the character which includes the pigmenting, opacifying material, applied either as a continuous coat or the microscopic spottings, as hereinbefore described.

While I have mentioned that the coating II may contain a binder of a cellulose compound or resin or both, with or without plasticizers, as the film forming application, and where applied in the form of microscopic spottings or dots, as in a half tone or an etched plate in that the gum desirable for the fiaps I6 and I8 may adhere thereto, it will be understood that the coating l I may be formed of an emulsion type material which contains gelatin or water soluble gums, dispersed with the water insoluble film forming material.

Accordingly, initially the film forming material Il may comprise one of the water soluble materials, such as gelatin, casein, starch, dextrin, sugar, dispersed in the organic binders, nitrocellulose, resin, plasticizer, etc. in the respective solvents for these organic materials, until an emulsion is formed and this emulsion is then applied to form the coating I I and after separation of the water and organic solvents, form a normally dry coating of thermoplastic character for carrying out the process of my invention described in the patent and co-pending application. Where the emulsion type coating is employed, the plasticizer for the nitrocellulose resin or both may be of the character which also serves a as plasticizer for glue, such as p-toluene sulfonamide.

While I have described a container blank Ii] in which the film forming material II is of thermoplastic material, itself dry normally and compatible with the adhesive carried by the transparent patch 2|, or in which the coating itself may serve as the adhesive film for uniting the patch where this is uncoated, and in which the film forming material II preferably includes the pigmenting material to opacity the paper or to obliterate and render undiscernible the contents of the envelope, where the coating is applied as an ornamenting material, it will be understood that certain novel features of my invention may be secured, to speed up the sealing of the patch to the container body, where the patch contains a film forming material of thermoplastic or solvent activatable character, where the stock for forming the container or envelope is merely impregnated with minute quantities of a plasticizer for the adhesive film carried by the patch.

Thus, the paper stock Ill may have a microscopic quantity of a plasticizer, such as tricresyl phosphate or some of the high boiling Cellosolves. From 1 to 5% will not visibly affeet the paper, except to make it softer. Plain paper, tinted paper or ornamented paper may be treated with from 1 to 5% of the plasticizer, without showing any appreciable tack, and this stock may then be used in the envelope forming operations for the thermoplastic sealing process for applying the transparency 20.

Thus, in general, while I prefer to employ a coating II of thermoplastic character or one which is compatible with the adhesive of the patch and containing organic binders of thermoplastic character, plain paper may be partially impregnated with a plasticizer or tinted or printed ornamented paper, particularly those using printing inks of non-thermoplastic character, may be merely treated with a plasticizer to speed up the thermoplastic sealing of the transparency to the body of the container, such as the envelope.

Where the coating I I or the plasticizer is of the character which is compatible with water soluble gums, the gum coatings I1 and I9 necessary for forming the sealing flap and the back flap may be directly applied over the coating. Where, however, the film forming material I I is not conveniently compatible with the water soluble gums for forming the coatings I1 and I9, a procedure may be followed wherein an already stamped out or died out blank 23, such as shown in Figure 6, may have applied thereto the coating II, distributed over the entire area except to leave uncoated portions 24 on the sealing flap I6 and uncoated portions 25 on the back flap I8.

In this form of construction. the coating II is so chosen that it need not be compatible with water soluble gums. The uncoated portions 24 and 25 are then receptive to the usual water soluble gums which may be applied to the sealing flap and back flap I8 at the uncoated portions 24 and 25, respectively, on these members.

In connection with the embodiment illustrated in Figure 6, the coating I I may be applied to the blank 23 by printing rolls, sprays, brushes, etched plates, and be of quick drying character, the blank thereafter being fed adjacent applicators which apply the gum coatings I1 and I9 upon the areas 24 and 25, respectively. The blank may then proceed to the patch sealing operation wherein heat and pressure, with or without solvent activation, serve intimately to seal a patch 20 in position, in a manner already described.

As a variation of the embodiment disclosed and described in connection with the above method, an envelope blank as illustrated in Figure 6, may have applied continuously thereovera plasticizer which renders the paper rapidly compatible with water insoluble, thermoplastic adhesives. The paper itself may be plain or impressed on the surface to form the interior of the envelope, with printing ink to ornament and serve as an opacifying layer, but not necessarily printing ink which is thermoplastic in character. With such a blank, the localized areas may be coated With a thermoplastic adhesive film which sets upon evaporation of the solvent, to a dry, non-tacky condition. This thermoplastic film may be applied to the localized areas outlined by the blank spaces 24 on the sealing fiap I6 and the blank spaces 25 on the back flap I8. This may be accomplished at the zones of activity in the envelope making machines well known today instead of the water soluble gum coating, and after this operation, the envelope blank passes to the patch sealing and envelope folding operation. The coating applied to the localized area 24 may be permitted to dry. The sid flaps I5 are, during this operation, folded and then the back flap sealed thereover, to join the side flaps to the back flap it, to complete the envelope forming operation, heat and pressure being utilized to accomplish thesamathis being immediately preceded by the heat sealing step to attach the patch 28 over the cutout or window 54.

The initial treatment of the paper with a plasticizer has the desirable eifect of accelerating the heat sealing operation between the patch and the envelope body 23', as well as to accelerate the heat sealing of the back flap l8 to the side flaps I 5, in completing the envelope forming operation. Additionally, the application of thermoplastic adhesive to the localized areas 25 need be in comparatively narrow strips of and the subsequent sealing operation by heat and pressure will effect a union between the back flap I 8 and the front face of the side flaps IS, without any loose edges, in addition to expediting the heat sealing operation at speeds unattainable b wet gum procedure.

In addition, the local application of thermosetting adhesive, as may be applied to the portion 24 of the sealing flap it permits a sealing area which need not be water activatable but is in the nature of a self-sealing adhesive.

After the envelope contents have been filled into the envelope, the sealing flap it may be sealed into position by pressure, preferably with heat, by passing the envelope, with the flap folded into sealing position, through pressure rolls which: are preferably heated. The plasticizer carriedby the paper makes it possible to use the thermo-setting adhesive applied to the sealing flap it at the area 24 by pressure, with or without heat, whereas otherwise ordinary calendered paper requires activation of a gum or an additional layer upon the envelope body to effect the cohesion between contiguous layers of selfsealing adhesives.

Thus,'it will be apparent that the application of a material to the envelope body which renders the same compatible with the adhesive carried by the transparent foil may be extended to render the adhesive on the back flap l8 compatible therewith in the envelope forming operation, as well as in the envelope sealing operation, where this ther'mo-setting adhesive is applied to the sealing flap IE on the localized area 24.

It will thus be observed that by the procedure described, I have provided a method for forming windowed containers, preferably envelopes, in which intimate sealing of the transparency may be accomplished, with high speeds of operation, and simultaneously achieving, in instances mentioned, the production of an opacified container, permitting the use of thinner grades of paper.

It will also be observed that I have provided a method for rendering paper body material available for heat sealing by providing it with a material rendering it compatible to normally dry thermoplastic adhesives which may be carried by an envelope or similar'container part, thereby providing what may be referred to as a self-sealing union. I It isto be understood that where I refer to opacified containers'or envelopes, this includes a coating or treatment which renders the paper stock substantiallyopaque so that any printing matter within an envelope is not readable therethrough, or may have, such ornamental configuration that while the'envelope is more or less translucent, the nature of the ornamentation blends with the written matter filled within the container, to make undiscernible the writing upon the insert. r

Having thus described my invention and illustrated its use, what I claim as new and desire to secure by Letters Patent, is:

1. In a method of uniting a transparency to other envelope material by heat sealing the parts which comprise a body element of paper and a foil of substantially transparent material constituting a window pane, and which overlies a cut-out or window in said body element, the steps which include providing the body material with a substantially uniform coating of a material which renders the same compatible with a thermoplastic adhesive interposed between said body and the foil, then placing the foil in overlapped position over the cut-out and applying localized heat and'pressure to the foil in the region of the overlap.

2. A method in accordance with claim 1, in which the adhesive is a film carried by the foil and in which the coating applied to the body element contains a plasticizer, said film and said coating being in a normally dry condition.

3. A method in accordance with claim 1, wherein the application of the coating to the body material is in the form of minute closely spaced discrete particles or spottings leaving an area uncoated between said particles.

4. A method in accordance with claim 1, wherein the application of th coating to the body material is in the form of minute closely spaced discrete particles or spotting leaving an area uncoated between said. particles, said coating opacifying the paper to an extent obscuring the contents when formed into an envelope.

5. A method in accordance with claim 1 Wherein the body material is an envelope stock paper and the application provided to the same is a thermoplastic printing ink distributed to opacify the paper and is applied by a printing surface to leave a surface compatible with water soluble gum adhesives forming part of the envelope making procedure, said application being discontinuous, to permit permeation to the paper by said soluble gum.

6. A method in accordance with claim 1 wherein the body material is the body of an envelope blank formed with a cutout and in which the body has extending therefrom a back flap and a sealing flap and in which the application provided to the same is a thermoplastic coating of printing ink incompatible with water soluble gums, and is also applied to said flaps within limits to exclude localized areas adjacent the back flap and sealing flap and to leave the latter uncoated and compatible with water soluble gum, and applying gum adhesive to the uncoated areas prior to the envelope forming operation.

'7. A method in accordance with claim 1 wherein the body element has applied thereto a printing ink solution having thermoplastic adhesive properties, by contacting the same with a transfer surface carrying the ink and having a discon tinuous surface characterized by the effect produced by a deposit from those surfaces of the group consisting of half tone plates, etched plates, intaglio plates, to leave a deposit comprising spottings and then permitting said ink to dry by evaporation of the solvents, and in which the foil has a thermoplastic adhesive surface compatible with the printing.

' 8. In a method of making window envelopes, the steps which include providing envelope paper with a substantially continuous opacifying, thermoplastic, normally dry and non-tacky coating, forming an envelope blank therefrom including a cutout, then providing a patch comprising a transparency, overlapping the cutout and heat sealing the overlapping portion by applying heat and pressure thereto to unite the patch to the envelope.

9. In a method of making windowed containers of the character including envelopes, the steps which comprise ornamenting paper over substantially the entire surface with a thermoplastic printing ink surface compatible with water soluble gums and also compatible with water insoluble adhesives of thermoplastic character, then forming a window cutout in said paper and uniting a transparencey over said cutout by heat and pressure applied to an overlapping portion of said transparencey.

10. A method in accordance with claim 9 which includes forming an envelope blank having a back flap, side flaps and sealing flap and applying water soluble gum to the flaps, followed by steps to complete the envelope forming operation.

11. A container of the character described comprising a body portion substantially the entire body of which is compatible with water insoluble thermoplastic adhesives characterized by having thereon a surface application comprising a plasticizer, another portion thereof having on localized areas, a coating of a water insoluble thermoplastic adhesive and united to said second portion, whereby a body portion is intimately united to the portion having the localized areas of the thermoplastic adhesive.

12. A windowed container of the character described comprising a body portion of paper having an application of a surface coating of a normally dry thermoplastic opacifying adhesive, a cutout forming a window and a transparency overlapping the cutout or window and united thereto by a film of fused water insoluble adhesive thereby increasing the intimacy of union between the body and transparency.

13. A Windowed container in accordance with claim 12 wherein the transparency is sealed at a peripheral edge to avoid a loose edge at the portion so united.

14. A windowed envelope comprising paper stock opacified by an imprinted thermoplastic adhesive printing ink characterized by the effect produced by a deposit from a printing surface taken from the group of half tone plates, intaglio plates, etched plates, to leave a discontinuous surface of such ink and in which other portions thereof, comprising parts of the container forming portion, are receptive to water soluble adhesive, and are united together by water soluble gum.

15. A container comprising paper stock the interior of which is uniformly coated with a water-insoluble thermoplastic coating composition, said coating being comprised of discrete particles as produced by a printing surface taken from the group consisting of half tone plates, intaglio plates, etched plates, leaving a substantial area uncoated between said particles, said treat-ed surface of said stock being united to a transparent window pane by said heat activated thermoplastic adhesive, whereas other parts of said container are unitable by a water-soluble gum applied to said areated surface.

ROBT. L. GRAY. 

